Surgeproof pilot switch



Aug. 17, 1937. c. N. HARDIN SURGEPROOF PILOT SWITCH Filed Dec. 27, 1933ad IIN.

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)P ,rv u@ vut L in HEEEM Patented Aug. 17, 1937 `UNITED STATESSUBGEPBOOF PILOT SWITCH Charles N. Hardin, Sulphur, Okla., assigner o!one-eighth to William A. Emerson, Sulphur,

Okla.

applicatie December e1, 1933, serai No. '104,196

3 Claims.

This'invention relates to a surge-proof pilot switch, one field of usefor which is in connection with city water-pumping equipment with a viewtoV maintaining the water in the stand pipe 5 within a few feet of thatrecommended by the manufacturer of the equipment. At the same time, itis to be understood that the invention is capable of general use andapplication and is therefore not to -be limited to the specific purposementioned.

A more specific object is to provide a pilot switch for controlling themotor of the pumping equipment and which switch is operable according tothe pressure of the water pumped by that equipment.

An important object is to provide such a pilot switch as is controlledby vacuum tube apparatus.

Another important object is to provide a cono struction wherein the timerequired for the necessary heating and cooling of the cathode isvariable and may be regulated, thus giving any desired time lag, andrendering the switch unaected by pressure surges.

'I'he more specific objects and advantages will become apparent from aconsideration of the description following taken in connection withaccompanying drawing illustrating an operative embodiment. y

In said'drawingz- The view shows the apparatus in electrical diagram.

Referring specifically thereto, alternating current from any suitablesource is conducted by wires III to the primary LI of a transformer I2having secondary wiring or coils at I3 and I4.

For example, primary I I may receive electric cur-- rent of 110 volts,60 cycles, while the secondary I3 receives electric current of 6.3volts, .4 ampere and the secondary I4 receives 220 volts, .05 ampere.

Vacuum tubes I5 and IG, for instance of type 237 as used in radiotelephony, are shown employed, the cathodes I1 thereof being connectedby a conductor I3 from which a conductor I9 leads to the secondary I4.From the same secondary I4, -a conductor 2li leads to a conductor 2|having coils 22 and 23 therein respectively adapted to actuate and beingassociated with relays 24 and 25. From the conductor 2|, conductors 26and 26' lead to the plates 21 and 21' within the tubes I5 and I8.

The filaments or heaters 23 of the tubes Iii and I3 are connected by aconductor 2l and from the filament 23 of the tube I5 a conductor 33leads to a contact 3i of a pressure gauge 32. A conductor 33 leads fromthe filament 23 of the tube I6 to a contact 34 of said pressure gauge32.' In the conductors 3l and 33, heavy duty rheostats 35 and 3la`areincorporated as shown. A conductor 35' connects conductor 23 to thesecondary I3 and from the same secondary a conductor 36, grounded at 31,leads to a movable contact 33 of the said pressure gauge 32. While apressure gauge has been specifically referred to, yet it is to beunderstood that the element 32 may represent contacts or a relay in alight sensitive cell circuit or be any other means or lead to any othermeans of making and breaking an electric circuit at high and lowpressure or vacuum.

The relays 24 and 23 may be a type as manufactured by Struthers DunnInc., Philadelphia, Pennsylvania, according to Patent No. 1,646,888. Anyother type of relay, however may be used.

It will be realized that when the coils 22 and 23 are deenergized, thecontacts 23h of the relay 24 are closed while the contacts 23a oftherelay 25 remain in normally open position. A conductor 39 connects oneside of both relays and has a conductor 43 leading therefrom whileconductors 4I and 4I lead from the other side of each relay. Theconductors 43, 4I and 4I are adapted to be operatively connected to theoperating motor M of the centrifugal pumping mechanism previouslyreferred to or to the line starter for that motor in the diagrammatic orconventional manner shown, 42 being a line switch having an interlock43. An actuating coil is provided for said switch 42 at 44.

When the water pressure reaches the low point, the pressure gaugeoperated by that water, moves contact 33 into engagement with contact34, causing current to flow through the filament 23 of tube I6. As aresult, the cathode of vacuum tube I6 is heated and the coil 23 isenergized closing the switch 23 which has the effect of closing the linestarter for the motor of the pump, such action being equivalent topushing an on button of a line starter.

When such motor starts and the pump begins discharging, the pressure isimmediately increased by the amount of the friction head which issufficient in any case to open the contacts 33 and 34, allowing thevacuum tube I6 to immediately cool oil.' and remain idle until the nextstart is performed.

When the pressure builds up to the high point, the contact 33 engagescontact 3I of the pressure gauge, causing a similar action to take placein the relay 2l and vacuum tube i5, which has the effect oi.' moving thestarter switch for the motor of the pump to an o position. When suchmotor stops, the pressure then decreases by the amount of the frictionhead which opens the high pressure contacts and the vacuum tube I 5cools off, and remains cool until the next stop is performed. l.

In both of said operations the rheostats 35 determine the time requiredfor the cathode to heat and may be varied, for example, fromapproximately seventeen seconds to one andonehalf minutes, however, thetime necessary for the cathode to cool will remain approximately thesame at any setting of relays 24 and 25 and is approximately nineseconds. Such diierence of time necessary for heating and cooling of thecathode renders the present device successful and not aected by pressuresurges.

Attention is called to the fact that the present invention is alsoadaptable among other uses, to acting as an automatic starter forelectric motor driven centrifugal pumps installed in deep wells such asare used in irrigated areas and in the oil fields. For such use,t thetime delay periods may be increased over that previously suggested toCil say to one and one-half to two or more minutes.

This can be accomplished by connecting two or more of the vacuum tubesin circuit in series.

Various changes may be resorted to provided they fall within the spiritand scope of the inven.

tion.

I claim as my invention:-

1. In combination with a control device having a gauge for pressuredeveloped therein, a pressure moveable arm on said gauge, vacuum tubesof the two element type having a common conductor connected to theircathodes, each tube having another conductor connected to the gauge andto their filaments and engageable one at a time by said arm, a conductorconnecting the filaments, a conductor having relay coils thereinconnected to the plates of said tubes, ilrst and second windings, saidfirst conductor branching to the last mentioned conductor through theiirst winding. a conductor connecting the iliaments branching throughthe second winding to said arm, the closing of one relay operating thedevice to on position and the closing of the position,

connected to their cathodes, each tube having another conductorconnected to the gauge and to their filaments and engageable one at atime by` said arm, a conductor connecting the iliaments, a conductorhaving relay coils therein connected to the plates of said tubes, firstand second windings, said' first conductorvbranching..`

to the last mentioned conductor through the first winding, a conductorconnecting the iliaments branching through the second winding to saidarm, the closing of one relay operating the device to on position andthe closing of the other relay moving the device to oi position, andmeans to energize said windings, each conductor connected to thefilaments having a rheostat therein.

3. In combination with a control device having a gauge for pressuredeveloped therein, a pressure movable arm on said gauge. vacuum tubes-ofthe two element type having a common conductor connected to theircathodes, each tube having another conductor connected to the gaugeandto their laments and engageable one at a time by said arm, a conductorconnecting the filaments, a conductor having relay coils thereinconnected to the plates of said tubes, said iirst conductor branching tothe 'last mentioned conductor, and the conductor connecting theiliaments branching to said arm, and means to supply current, theclosing of one relay operating the device to on position and the closingof the other relay moving the device to off position.

CHARLES N. HARDIN'.

